Auditory Warning Research Articles

Adaptation changes in dynamic postural control and contingent negative variation during repeated transient forward translation in the elderly

BackgroundAdaptation changes in postural control and contingent negative variation (CNV) for the elderly were investigated during repeated forward floor translation.MethodsFifteen healthy elderly persons, living in the suburban area of Kanazawa City, Japan, underwent backward postural disturbance by a forward-floor translation (S2) 2 s after an auditory warning signal (S1). A set with 20 trials was repeated until a negative peak of late CNV was recognized in the 600-ms period before S2, and the last set was defined as the final set. Electroencephalograms, center of foot pressure in the anteroposterior direction (CoPap), and electromyograms of postural muscles were analyzed.ResultsCoPap displacement generated by the floor translation was significantly decreased until the twelfth trial in the first set, and mean CoPap displacement was smaller in the second and final sets than in the first set. The mean displacement was significantly smaller in the final set than the previous set. A late CNV with a negative peak was not recognized in the first and second sets. However, most subjects (13/15) showed a negative peak by the fourth set, when the late CNV started to increase negatively from about 1,000 ms after S1 and peaked at about 300 ms before S2. At about 160 ms before the CNV peak, the CoPap forward shift started. The increase in timing of the gastrocnemius activity related to the CoPap shift was significantly correlated with the CNV peak timing (r = 0.64). After S2, peak amplitudes of the anterior postural muscles were significantly decreased in the final set compared to the first set.ConclusionsIt was demonstrated that even for the elderly, with so many repetitions of postural disturbance, a late CNV with a negative peak was recognized, leading to accurate postural preparation. This suggests the improvement of frontal lobe function (e.g., anticipatory attention and motor preparation) in the elderly.

Influence of anxiety, depression and looming cognitive style on auditory looming perception

Previous studies show that individuals with an anticipatory auditory looming bias over-estimate the closeness of a sound source that approaches them. Our present study bridges cognitive clinical and perception research, and provides evidence that anxiety symptoms and a particular putative cognitive style that creates vulnerability for anxiety (looming cognitive style, or LCS) are related to how people perceive this ecologically fundamental auditory warning signal. The effects of anxiety symptoms on the anticipatory auditory looming effect synergistically depend on the dimension of perceived personal danger assessed by the LCS (physical or social threat). Depression symptoms, in contrast to anxiety symptoms, predict a diminution of the auditory looming bias. Findings broaden our understanding of the links between cognitive-affective states and auditory perception processes and lend further support to past studies providing evidence that the looming cognitive style is related to bias in threat processing.

Failure to detect critical auditory alerts in the cockpit: evidence for inattentional deafness.

The aim of this study was to test whether inattentional deafness to critical alarms would be observed in a simulated cockpit. The inability of pilots to detect unexpected changes in their auditory environment (e.g., alarms) is a major safety problem in aeronautics. In aviation, the lack of response to alarms is usually not attributed to attentional limitations, but rather to pilots choosing to ignore such warnings due to decision biases, hearing issues, or conscious risk taking. Twenty-eight general aviation pilots performed two landings in a flight simulator. In one scenario an auditory alert was triggered alone, whereas in the other the auditory alert occurred while the pilots dealt with a critical windshear. In the windshear scenario, II pilots (39.3%) did not report or react appropriately to the alarm whereas all the pilots perceived the auditory warning in the no-windshear scenario. Also, of those pilots who were first exposed to the no-windshear scenario and detected the alarm, only three suffered from inattentional deafness in the subsequent windshear scenario. These findings establish inattentional deafness as a cognitive phenomenon that is critical for air safety. Pre-exposure to a critical event triggering an auditory alarm can enhance alarm detection when a similar event is encountered subsequently. Case-based learning is a solution to mitigate auditory alarm misperception.

Music as an Auditory Display

Currently, there are very few guidelines on parameters needed to create an effective auditory display. Auditory displays can be intrusive and may not be used effectively if they are poorly designed. However, music is often in our environments as ambient noise and, instead of being intrusive, can be perceived as making the environment calmer and more productive. We present the initial steps of exploring the option of using music as a medium to develop an auditory display capable of conveying normal state information and warning information. An important feature that may impact the effectiveness of auditory warnings is perceived urgency: the impression of urgency that a sound evokes on a listener. To explore whether music could convey urgency as needed for auditory warnings, we evaluated four different musical phrases that varied in time and key signature as a method of measuring the effects of mode and tempo on perceived urgency. The effectiveness of the study was tested with twenty subjects split into a two by two factorial design: gender (male vs. female) and musical experience (experienced vs. non-experienced). The applications of this research can help develop concrete guidelines when designing effective auditory displays in order to improve users’ performance when dealing with complex interfaces.

Evaluating Driver Behavior Toward Innovative Warning Devices at Railway Level Crossings Using a Driving Simulator

Control at railway level crossings, using either road rumble strips or in-vehicle auditory warning devices, has the potential to improve safety. This article evaluates driver behavior of these two devices and two conventional crossing devices (flashing lights and a stop sign) using a driving simulator. Rumble strips have been seen to encourage drivers to reduce speed earlier on approach to a level crossing but did not affect stopping compliance. In-vehicle auditory warnings have produced high compliance and, overall, have produced behavior comparable to that seen for conventional flashing lights. However, the detailed design features of such devices require further development before more concrete conclusions can be drawn. Contributing factors of age, gender, speed, and types of warning devices were all found to significantly affect driver behavior at crossings. Overall, the results indicate that drivers behave differently and demonstrate higher signal compliance at actively protected crossings than at passively protected crossings for alternative and conventional warning devices.

On Evaluation and Localization of Auditory Warning Devices for Adequate Audibility

This paper presents an analytic procedure to assist safety practitioners in evaluating the audibility of an existing auditory warning system in their workplaces. Two alarm location models are described: (a) a model with an unknown signal sound level, and (b) a model with a known signal sound level. A heuristic algorithm to determine a minimum number of alarm devices and their locations so that the warning signals can be clearly heard by workers is also proposed. The algorithm considers the ambient noise level, noise levels generated by individual machines, locations where workers are likely to be present, and noise levels at worker locations. From the numerical examples and the computation experiment, both the optimization and heuristic approaches yield solutions that satisfy the 15-dBA constraints. The heuristic approach is efficient in solving large alarm location problems due its capability to find near-optimal solutions within reasonable computation time.

Innovative system for real-time ergonomic feedback in industrial manufacturing

This work presents a system that permits a real-time ergonomic assessment of manual tasks in an industrial environment. First, a biomechanical model of the upper body has been developed by using inertial sensors placed at different locations on the upper body. Based on this model, a computerized RULA ergonomic assessment was implemented to permit a global risk assessment of musculoskeletal disorders in real-time. Furthermore, local scores were calculated per segment, e.g. the neck region, and gave information on the local risks for musculoskeletal disorders. Visual information was fed back to the user by using a see-through head mounted display. Additional visual highlighting and auditory warnings were provided when some predefined thresholds were exceeded. In a user study (N = 12 participants) a group with the RULA feedback was compared to a control group. Results demonstrate that the real-time ergonomic feedback significantly decreased the outcome of both globally as well as locally hazardous RULA values that are associated with increased risk for musculoskeletal disorders. Task execution time did not differ between groups. The real-time ergonomic tool introduced in this study has the potential to considerably reduce the risk of musculoskeletal disorders in industrial settings. Implications for ergonomics in manufacturing and user feedback modalities are further discussed.

Improving the discriminability of simultaneous auditory alarms using principles of voice-leading found in music

Predicting the ability of listeners to discriminate between simultaneous auditory streams is a longstanding challenge in the design of auditory displays. The creation of an efficacious artificial auditory scene can require an immense amount of knowledge about how sounds are heard and interpreted; what is commonly called auditory scene analysis. Fortunately, musicians have been constructing novel auditory scenes with multiple simultaneous streams for many centuries, and the rules governing the composition of Western polyphonic music have even been explicitly codified in a range of techniques referred to as “voice-leading”. These relatively simple but effective rules have the potential to help guide designers of auditory displays by maximizing the distinctions between concurrent signals. An experiment was conducted to measure the discriminability of alarms designed with musical “voice-leading” features as compared with existing alarms from Learjet 31a and Learjet 35 aircraft. Signals designed with the auditory scene synthesis techniques embedded in musical “voice-leading” were found to significantly improve discriminability for up to five simultaneous alarms. By applying these principles to warning signals, this study has sought to implement a system for creating new auditory warnings that contain more efficient differentiating properties and furthermore conform to a more unified stylistic identity.

Warn me now or inform me later: Drivers' acceptance of real-time and post-drive distraction mitigation systems

Vehicle crashes caused by driver distraction are of increasing concern. One approach to reduce the number of these crashes mitigates distraction by giving drivers feedback regarding their performance. For these mitigation systems to be effective, drivers must trust and accept them. The objective of this study was to evaluate real-time and post-drive mitigation systems designed to reduce driver distraction. The real-time mitigation system used visual and auditory warnings to alert the driver to distracting behavior. The post-drive mitigation system coached drivers on their performance and encouraged social conformism by comparing their performance to peers. A driving study with 36 participants between the ages of 25 and 50 years old (M=34) was conducted using a high-fidelity driving simulator. An extended Technology Acceptance Model captured drivers' acceptance of mitigation systems using four constructs: perceived ease of use, perceived usefulness, unobtrusiveness, and behavioral intention to use. Perceived ease of use was found to be the primary determinant and perceived usefulness the secondary determinant of behavioral intention to use, while the effect of unobtrusiveness on intention to use was fully mediated by perceived ease of use and perceived usefulness. The real-time system was more obtrusive and less easy to use than the post-drive system. Although this study included a relatively narrow age range (25 to 50 years old), older drivers found both systems more useful. These results suggest that informing drivers with detailed information of their driving performance after driving is more acceptable than warning drivers with auditory and visual alerts while driving.

Adaptation changes in dynamic postural control and contingent negative variation during backward disturbance by transient floor translation in the elderly

BackgroundWe investigated adaptation changes in dynamic postural control and contingent negative variation (CNV) in 13 young and 12 elderly adults. Subjects repeatedly underwent backward postural disturbance by a forward floor translation (S2) 2 s after an auditory warning signal (S1). Initial and second sets were conducted, each set with 20 trials. Posterior peak position of the center of pressure in the anteroposterior direction (CoPy) after S2 was identified. Electroencephalograms from Cz were averaged for each set, and the CNV negative peak was identified.ResultsCompared with the first trial, the posterior peak position of CoPy changed significantly forward from the 12th trial in the young and from the 19th trial in the elderly during the initial set. The mean of the posterior peak position was more forward in second set than in the initial set for both groups and was significantly backward in the elderly compared to the young for both sets. These findings indicate that subjects in both groups adapted better to the postural disturbance in the second set than in the initial set, and the adaptation was later in the elderly. Late CNV in the young started to increase negatively from the middle of the S1-S2 period and peaked just before S2. Peak CNV amplitude was larger in the second set than in the initial set. In contrast, late CNV in the elderly exhibited no negative increase as in the young and peaked in the middle of the S1-S2 period, which was followed by gradual decreasing toward S2. No adaptive changes were found in late CNV for the elderly.ConclusionsIt is conceivable that reduced activation of the frontal lobe may be one of the factors contributing to the decrease in postural adaptability in the elderly. The elderly may use various brain regions for the adaptation of dynamic postural control compared with the young.

Urgent alarms in trucks: effects on annoyance and subsequent driving performance

Previous research has shown that urgent auditory warnings are likely to annoy drivers. Increased urgency could also raise drivers’ stress levels, which in turn could impact their ability to detect and react to subsequent changes in the traffic environment. We conducted a simulator experiment with 24 truck drivers to investigate the potential of urgent alarms to raise annoyance and negatively affect drivers’ subsequent responses to unrelated, critical events on the road. The drivers received two types of warnings that were designed to significantly differ in perceived urgency. Several times in the trial, an unexpected event occurred just seconds after drivers were presented with an unrelated warning, and the drivers had to brake immediately to avoid a collision. The results indicate that acoustic characteristics and semantic meaning may impact the perceived annoyance of in-vehicle warnings. Interestingly, we found a significant, negative correlation between the drivers’ experience (years of truck driving experience) and the rated annoyance for both types of warnings. Also, the drivers who received the high-urgency warning braked significantly harder and tended to brake later than the drivers who received a low-urgency warning. These results have implications for ITS systems for heavy vehicles that intend to implement auditory warning signals.

Assessing Attentional Systems in Children with Attention Deficit Hyperactivity Disorder

The aim of this study was to evaluate the efficiency and interactions of attentional systems in children with Attention Deficit Hyperactivity Disorder (ADHD) by considering the effects of reinforcement and auditory warning on each component of attention. Thirty-six drug-naïve children (18 children with ADHD/18 typically developing children) performed two revised versions of the Attentional Network Test, which assess the efficiency of alerting, orienting, and executive systems. In feedback trials, children received feedback about their accuracy, whereas in the no-feedback trials, feedback was not given. In both conditions, children with ADHD performed more slowly than did typically developing children. They also showed impairments in the ability to disengage attention and in executive functioning, which improved when alertness was increased by administering the auditory warning. The performance of the attentional networks appeared to be modulated by the absence or the presence of reinforcement. We suggest that the observed executive system deficit in children with ADHD could depend on their low level of arousal rather than being an independent disorder.

The Development of Parameters and Warning Algorithms for an Intersection Bus-Pedestrian Collision Warning System

This study presents the conceptual design of an intersection bus-pedestrian collision warning system for bus drivers approaching an intersection. The basic parameters of the proposed design concept include the bus drivers’ perception-reaction time, the emergency deceleration rate of the bus, and pedestrian walking speed. A bus driving simulation was designed and conducted to analyze bus drivers’ responses to unexpected pedestrians crossing unsignalized intersections or signalized intersections during a green light interval for parameter analysis. The timings of auditory warnings and visual warnings, the locations for vehicle detectors and pedestrian detectors, and the locations for visual warning devices were also developed after analyzing the experimental results. The experimental results also highlight some important characteristics of bus driving behavior at intersections. Moreover, bus drivers really pay attention to the warning messages. Finally, this study develops and discusses some warning algorithms.

Ecological interface design inspired human machine interface for advanced driver assistance systems

The development and evaluation of an integrated advisory interface for several advanced driver assistance systems (ADAS) is focused here. It was developed using an ecological interface design (EID) approach and was combined with the type of auditory warnings used in vehicles today to investigate multiple-staged warnings. The warning combination was evaluated using a fixed-base medium-fidelity driving simulator. The results suggest that the development of driver interfaces based on EID could benefit by being combined with the iterative nature of the user-centred design methods to make accurate assumptions on how the design is suitable for end-users in the context of use. Simulator results also show that participants drove with greater safety margins to lead vehicles and maintained better lateral positioning when driving with the interface, indicating that integrated multiple-staged warnings can have a positive effect on driver behaviour if correctly designed.

Looming Auditory Collision Warnings for Driving

A driving simulator was used to compare the effectiveness of increasing intensity (looming) auditory warning signals with other types of auditory warnings. Auditory warnings have been shown to speed driver reaction time in rear-end collision situations; however, it is not clear which type of signal is the most effective. Although verbal and symbolic (e.g., a car horn) warnings have faster response times than abstract warnings, they often lead to more response errors. Participants (N=20) experienced four nonlooming auditory warnings (constant intensity, pulsed, ramped, and car horn), three looming auditory warnings ("veridical," "early," and "late"), and a no-warning condition. In 80% of the trials, warnings were activated when a critical response was required, and in 20% of the trials, the warnings were false alarms. For the early (late) looming warnings, the rate of change of intensity signaled a time to collision (TTC) that was shorter (longer) than the actual TTC. Veridical looming and car horn warnings had significantly faster brake reaction times (BRT) compared with the other nonlooming warnings (by 80 to 160 ms). However, the number of braking responses in false alarm conditions was significantly greater for the car horn. BRT increased significantly and systematically as the TTC signaled by the looming warning was changed from early to veridical to late. Looming auditory warnings produce the best combination of response speed and accuracy. The results indicate that looming auditory warnings can be used to effectively warn a driver about an impending collision.

Slow eye movement as a possible predictor of reaction delays to auditory warning alarms in a drowsy state

In recently developed intelligent vehicles, warning alarms are often used to prompt avoidance behaviours from drivers facing imminent hazardous situations. However, when critical reaction delays to auditory stimulation are anticipated, the alarm should be activated earlier to compensate for such delays. It was found that reaction times to an auditory stimulus significantly increased in the presence of slow eye movement (SEM), which is known to occur frequently during the wake–sleep transition. The reaction delay could not be attributed to temporal effects such as fatigue and was invariant regardless of response effectors (finger or foot). Moreover, it was found that applied pedal force decreased immediately after an auditory stimulus interrupted SEM. Consequently, it was concluded that SEM can be a good predictor of reaction delays to auditory warning alarms when drivers are in a drowsy state. Statement of Relevance:The present study demonstrated that simple auditory reaction time significantly increased when SEM emerged. In the design of vehicle safety systems using warning alarms to prompt avoidance behaviours from drivers, such reaction delays during SEM must be taken into account.

Basic study on effectiveness of tactile interface for warning presentation in driving environment

It was investigated whether the important driving information such as a pedestrian in the right and left peripheral visual fields can be recognised faster using tactile warning system as compared with auditory warning system. The participants were required to simultaneously carry out a tracking task, a switch pressing task such as selection of light-on function, and a judgement task of important information which randomly appeared to the right or left peripheral visual field. The tracking error, the percentage correct of switch pressing, and the response time to the right or left peripheral stimulus were measured. It was examined how age, the modality of alarm presentation (auditory or tactile), and the directional cue affected the performance above. The response time of the tactile warning was shorter than that of the auditory warning. The addition of directional cue of warning presentation affected the performance, and the directional cue enhanced the performance.

Auditory Warning Signals Affect Mechanisms of Response Selection

Irrelevant tone (accessory) stimuli facilitate performance in simple and choice reaction time tasks. In the present study, we combined accessory stimulation with a selective attention paradigm in order to investigate its influence on mechanisms of response selection. In the framework of a spatial stimulus-response compatibility task (Simon task), we tested whether accessory stimuli selectively affect bottom up triggered response activation processes (e.g., direct route processing), processing of task-relevant stimulus features (indirect route processing), or both/none. Results suggest a two-component effect of accessory stimuli within this selective attention task. First, accessory stimuli increased the Simon effect due to beneficial direct route processing. Second, accessory stimuli generally decreased reaction times indicating facilitation of indirect route processing.

Loudness interacts with semantics in auditory warnings to impact rear-end collisions

► Auditory collision warning system (CWS) alarms can reduce crash probability if designed to convey appropriate hazard levels. ► Semantic and acoustics parameters of in-vehicle collision warning system (CWS) auditory alarms interact to effect driver response. ► Inappropriately hazard matched auditory warnings (extreme urgency or very low urgency) are ineffective. ► Auditory warning context impacts behavioral response and ratings of perceived urgency. ► The signal word “Notice” presented at a relatively high acoustic intensity of 85 dB and “Danger” presented at a relatively low acoustic intensity of 70 dB resulted in equal crash reduction probability and were perceived as having equivalent urgency levels. This study examined the impact of semantic and acoustics parameters of in-vehicle collision warning system (CWS) alarms on driver response. Thirty participants drove a simulated vehicle through scenarios containing five different unexpected hazard events. As drivers approached the hazard event one of four CWS alarms, counter balanced with the hazard event type, or no alarm (control) was presented. Alarms consisted of the signal word “Notice” or “Danger” presented at either 70 or 85 dBA. Rear-end collision events resulted in the highest crash rate, accounting for 45.4% of all crashes. In these scenarios, CWSs significantly reduced crash rates. CWS alarms with an intermediate urgency level achieved through an interaction of semantics and acoustics (“Danger” at 70 dB and “Notice” at 85 dB) resulted in significant reductions in crash probability. Providing an extremely urgent signal word, “Danger” at a high acoustically urgent presentation level – 85 dB was not effective in reducing crashes, nor was a low urgency signal word, “Notice” presented at a low acoustical urgency level – 70 dB. Implications of these results for the design and implementation of CWS systems and auditory alarms in general, are discussed.

선교내에서 청각경보음의 유형이 반응속도와 정확성에 미치는 영향

The effects of different auditory warnings on response time and accuracy were studied in a laboratory ship-bridge work environment. Subjective preference on the type of auditory warnings was also of a primary concern. Twenty five subjects were asked to select an appropriate button for the warning sound presented with three types of auditory warning (abstract sound, auditory icon, and voice alarm) and five levels of warning situation (fire, steering failure, collision, engine failure, and low power). Results showed that the response time and accuracy was significantly affected by the types of auditory warning. The voice alarm resulted in a higher accuracy and subjective preference, as compared to the auditory icon and abstract sound. Regarding the response time, auditory icons and voice alarms were equivalent and superior to abstract sounds. Actual or potential applications of this research include guidelines for the design of integrated ship bridge systems.